Mineral absorption in the black rhinoceros (Diceros bicornis) as compared with the domestic horse

To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for black rhinoceroses (Diceros bicornis), we investigated the apparent absorption (aA) of macro- and microminerals in eight black rhinoceroses from three zoological institutions in a total of 32 feeding trials with total faecal collection, with additional data from three unpublished studies (18 feeding trials). Feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Mn, Cu, Zn and Co. The resulting aA coefficients, and the linear relationships of apparently absorbable dietary mineral content to total dietary mineral content [per 100 g dry matter (DM)], were compared with data for domestic horses. Rhinoceroses had significantly higher aA coefficients for Ca and Mg (because of a higher calculated 'true' absorption), and lower ones for Na and K (because of calculated higher endogenous faecal losses). High absorption efficiency for divalent cations is hypothesized to be an adaptation to a natural diet of particularly high Ca:P ratio (approximately 14:1); an effective removal of Ca from the ingesta guarantees sufficient P availability at the fermentation site in the hindgut. Higher faecal losses of Na and K are hypothesized to be linked to a higher faecal bulk per DM intake in black rhinoceroses as compared with horses because of a generally lower digestive efficiency. There were no relevant differences in the absorption patterns of microminerals. In particular, there were no discernable differences in Fe absorption within the rhinoceroses for diets with and without tannin supplementation. Several of the zoo diets assessed in this study were deficient in Cu, Mn or Zn, and most contained excessive levels of Fe when compared with horse requirements. The findings of this study indicate that differences in mineral absorption between occur even between species of similar digestive anatomy; that in particular, Ca absorption might vary between hindgut fermenters with Ca:P ratio in their natural diet; that Na might be a particularly limiting factor in the ecology of free-ranging rhinoceroses; that moderate doses of tannins do not seem to markedly influence mineral absorption; and that diets for captive animals should contain adequate, but not excessive mineral levels.     

Effects of exogenous equine somatotropin on mineral balance in two-year-old horses in race training

This study examined the effects of exogenous equinesomatotropin (eST — Equigen) administration on mineral absorption and retention in two-year-old horses in race training. Sixteen Quarter Horse geldings were paired by age (ave.age=794 d), and one horse from each pair was assigned at random to either the eST treatment group or the control. The experiment was conducted over 112 days during which the horses were gentled to ride and trained on a dirt track in a regimen typical for race horses in training. At 28-day intervals, collections of total fecal and urinary output were made to determine effects on Ca, inorganic P, Mg, Cu and Zn mineral balance.Due to marginal and slightly deficient amounts (P<01)of Ca, P, Mg and Zn intake by days 84 and 112, a result of reduced feed intake to maintain a constant body condition in the presence of a decreased workload, mineral balance for the aforementioned minerals was only examined through day 56. In contrast to the previous minerals, Cu intake appeared adequate. Ca, P, Mg, Cu and Zn intake did not differ (P>.05) by treatment. The eST-treated horses increased (P<.05) Ca retention as a percent of Ca absorbed, had greater (P<.05) overall apparent efficiency of P absorption and greater (P<.05) apparent retention of P on day 56 than the control horses. The eST-treated horses had greater (P<.05) apparent Cu absorption on day 56, greater (P<.05) apparent Cu absorption efficiency on days 56 and 84, and there was a trend (P<.1) for the eST-treated horses to retain more Cu on day 56 than the control horses. Finally, the eST-treated horses retained a greater percent (P<.1) of absorbed Zn on day 56.     

Content and distribution of macro- and micro-elements in the body of pasture-fed young horses

OBJECTIVE: To determine the content and distribution of Na, K, Ca, P, Mg, S, Cu, Mn, Fe and Zn in the body of pasture-fed young horses and then use a factorial model to calculate the dietary mineral requirements for growth. PROCEDURE: Twenty-one foals were killed at about 150 days of age and the organs, soft tissues, skin and bones and a sample of muscle were dissected out and weighted. The mineral concentrations of elements in all soft tissues and bones were measured by inductively coupled emission spectrometry. The total mineral element composition associated with a tissue was determined from the weight of tissue and its mineral element concentration. RESULTS: Expressed as a percent of total body mineral elements, muscle contained 20% Na, 78% K, 32% Mg, 62% Cu, 36% Mn and 57% Zn, bone contained 47% Na, 99% Ca, 81% P, 62% Mg, 30% Mn and 28% Zn while the organs accounted for a smaller percentage ranging from 0.06% for Ca to 26% for Fe. In liver Cu accounted for 9.2% of total body Cu. Each kilogram of empty body weight was associated with 1.0 g Na, 2.5 g K, 17.1 g Ca, 10.1 g P, 0.4 g Mg, 1.1 mg Cu, 0.39 mg Mn, 52.5 mg Fe and 21.4 mg Zn. CONCLUSION: The mineral element content of body weight gain is a component used in the factorial model to determine dietary mineral element requirements for growth. The calculated dietary mineral requirements, expressed per kg dry matter, for a 200 kg horse gaining 1.0 kg/day were 1.0 g Na, 2.1 g K, 4.6 g Ca, 3.5 g P, 0.7 g Mg, 4.5 mg Cu and 25 mg Zn.     

Mineral Status and Interrelationship in Soil,Forage, and Blood Serum of Horses in the Rainy and Dry Seasons

The objective was to evaluate the content of P, Ca, Mg, K, Na, Cu, Fe, Zn, Se, and Mn in soil, forage, and serum of horses in several production units (PU) during rainy and dry seasons and predict their concentration in serum from their content in soil and forage. Soil and pastures were sampled in the dry (November–December) and in rainy seasons (June–July), and blood samples were collected from the jugular vein of 76 horses in both seasons at four PU. The experimental design was a completely random design within a 4 × 2 (PU × season) factorial arrangement of treatments. Concentration of minerals in soil differed (P < .05) among PU, and contents of P, Ca, Mg, and K were low; Zn and Fe were high; and Cu and Mn were adequate. Mineral concentrations in forage differed among PU and season, and among PU within season (interaction P < .05). Contents of Ca, Mg, Na, Zn, and Cu were low; Fe was high; and P, K, Se, and Mn adequate. The mineral concentration in equine blood serum differed (P < .05) among PU and season. Overall, there were deficiencies of P, Ca, Mg, Na, Cu, and Se, but adequate amounts of K, Zn, and Fe. There are imbalances of minerals in soil and forages which effected their concentration inequine blood.     

Mineral intake and hair analysis of horses in arizona

To evaluate the effect of diet on hair mineral content, 61 feeds, 31 pasture grasses, 29 mineral supplements, 31 water samples and hair samples from 391 horses from 31 ranches in Arizona were analyzed for fifteen minerals. Based on dietary histories and estimated intakes when free choice access was involved, mineral intake of the horses was calculated and compared to mineral content of the hair. Data were evaluated by regression analysis for correlations between hair and dietary minerals and variations in hair mineral content attributable to coat color, age, sex and breed.¹¹,¹²,¹³,¹⁴

There were differences (P<.05) in hair mineral content of horses of different breeds, coat colors, ages and sex, regardless of dietary intake. However, there were some significant correlations between feed mineral intake and hair mineral content. A few weak simple correlations (Ca:Ca, P:P, Na:Na, K:K) were found, but complex mineral correlations (Ca:P, Ca:Na, Zn:K, Fe:Zn etc.) were more common and had higher correlation coefficients (Table 7). Variations in mineral intake explained only 30% of the variation for a given hair mineral, with the exception of manganese. The multiple relationships between minerals and their effect on metabolism appear to have a greater effect on hair mineral content than a single mineral deficiency or excess¹⁷,¹⁸,²⁰,²¹ and may offer better insight to the interpretation of mineral nutrition than simple one to one correlations.     

Organic matter and macromineral digestibility in domestic rabbits (Oryctolagus cuniculus) as compared to other hindgut fermenters

It is generally assumed that animal species differ in physiological characteristics of their digestive tract. Because investigating digestive processes is often labour‐intensive, requiring lengthy adaptation and collection periods, comparisons are often made on the basis of data collated from different studies. We added a new data set on dietary crude fibre (CF) and macromineral (Na, K, Ca, P, Mg) composition and apparent digestibility (aD) of organic matter (OM) and macrominerals in rabbits (Oryctolagus cuniculus; a total of 180 measurements with 12 individuals and 10 different diets) to a literature data collection for rodents and domestic horses (Equus caballus). Significant negative relationships between dietary CF and aD OM were obtained, but the significant difference in digestive efficiency between rabbits and guinea pigs (Cavia porcellus) reported from studies where both species had been investigated under identical conditions were not detectable in the larger data collection. However, the 95% confidence interval of the negative slope of the CF–aD OM relationship did not overlap between domestic horses on the one hand, and rabbits and guinea pigs on the other hand, indicating a less depressing effect of CF in horses. Akaike's information criterion indicated that aD of a macromineral did not only depend on its concentration in the diet, but also on the individual and various other diet characteristics and the presence of other macrominerals, indicating complex interactions. The data indicate similar mechanisms in the absorption of macrominerals amongst rabbits, rodents and horses, with the exception of Na and K in guinea pigs and Ca in chinchillas (Chinchilla laniger) that should be further corroborated. In particular, the occurrence of high aD Ca in hindgut fermenters, regardless of whether they employ a digestive strategy of coprophagy or whether they have fossorial habits, suggests that this peculiarity might represent an adaptation to hindgut fermentation in general.     

Digestible energy intake, dry matter digestibility and effect of increased calcium intake on bone parameters of grazing Thoroughbred weanlings in New Zealand

AIMS: To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and the effects of increased calcium (Ca) intakes on apparent mineral absorption and bone characteristics in grazing weanling Thoroughbreds. METHODS: DM intake (DMI) and DEI were determined in 16 weanling Thoroughbreds grazing pasture from their daily faecal DM output, measured over 8 days, divided by the DM indigestible fraction (1-digestible DM) determined in a 6-day digestibility trial. The DM, gross energy content, crude protein, soluble carbohydrate, acid detergent fibre, neutral detergent fibre, lipid, Ca, phosphorus (P), sodium (Na), potassium(K), sulphur (S) and magnesium (Mg) composition of perennial ryegrass/white clover pasture and faeces were determined and their digestibility and/or apparent absorption calculated. Calcium intake and bone growth studies used 17 weanlings, randomly divided into three groups and fed perennial ryegrass/white clover pasture and 0.5 kg grain, with or without a CaCO3 supplement, for 84 days. The animals in Group 1 (n=6) were on a low Ca diet (3.5 g/kg DM) and were fed pasture only; those in Group 2 (n=5) were on a medium Ca diet (6.3 g/kg DM);and those in Group 3 (n=6) were on a high Ca diet (12.0 g/kg DM). After 44 days the apparent absorption of Ca was determined from the differences between the Ca intakes and faecal Ca outputs. At periods just before and after Ca supplementation the horses were anaesthetised and the left radius, third metacarpus(Mc3) and first phalanx of the left foreleg were scanned using a peripheral quantitative computed tomography scanner to determine cortical mineral content, density, area, periosteal circumference and bone strength. To investigate gastrointestinal tract transit time and DM digestibility, five randomly selected horses were administered Swiss screen bags on several occasions via a nasogastric tube. Each 60 x 10mm bag contained 3.21 (SE 0.37) g of frozen minced grass. Bags were recovered from the freshly passed faeces and frozen until analysis. RESULTS: The DM digestibility of the pasture was 0.62, while the DMI and DEI of weanlings (300 kg, gaining 0.7 kg/day) were 5.5 kg/day and 63 MJ/day, respectively. Increasing Ca intake had no significant effect on DEI, DM digestibility or on the apparent absorption of Ca, P, Na and K, but decreased the apparent absorption of Mg from 0.50 to 0.38. Regardless of Ca intake, the apparent absorption of Ca was 0.56. During the Ca administration trial there were significant increases overtime in the bone strength (strain stress index) of the proximal phalanx, Mc3 and radial diaphysis. However, the increase in bone strength was not associated with increase in dietary Ca, as neither the medium- nor high-Ca intake groups differed significantly from the low-Ca controls. The mean transit time for the Swiss screen bags was 25.46 (SE 0.09) h, and transit times were similar whether the horses were grazing or confined in loose boxes, being 26.64 (SE 0.23) h and 24.33 (SE 0.13) h, respectively. The DM digestibility determined using the bags was 0.54, which was significantly lower than the 0.62 determined by direct faeces collection. CONCLUSIONS: Good growth rates were achieved in Thoroughbred weanlings grazing perennial ryegrass/white clover pasture containing 3.5 g Ca/kg DM and a DE of 11.4 MJ/kg DM. Increasing dietary Ca intake 3.5-fold for 3 months had negligible impact on bone growth and development.     

Partitioning of nutrient and trace elements in feed between body retention,faeces and urine by growing dairy-breed steers

The partitioning of nutrients and trace elements from feeds, drinking water and mineral supplements on growth, faeces and urine of growing cattle was studied with eight steers in a balanced Latin square design with two replicates, each comprising four treatments (diet compositions), four periods and four animals. The treatments were four rations with a silage proportion of 15, 30, 60 and 100% of the dry matter. Records were taken of the individual intake of silage, concentrates, mineral supplements and water, and excretions by collecting all urine and faeces. All feeds, urine, faeces and water were analysed for their content of Al, Ca, Cd, Cl, Co, Cu, Fe, K, Mg, Mn, Mo, N, Na, Ni, P, S, Se, and Zn. Elements that were mainly excreted in faeces (Ca, Cd, Cu, Fe, P, and Zn) tended to have a constant uptake in amount. As there is a fairly good correlation between DM consumption and faeces production, it is possible to estimate the amount of these elements excreted at farm level by analysing a faeces sample. Elements that are excreted in significant amounts in both faeces and urine (Cl, K, Mg, Mo, N, Na, S, and Se) tended to have a constant uptake over treatments as a fraction of the feed content. It is more difficult to estimate the amounts of these elements at farm level because it is more difficult to predict urine production than faeces production.     

Effect of dietary calcium level and source on mineral utilisation by piglets fed diets containing exogenous phytase

Calcium and phosphorus are essential minerals, closely linked in digestive processes and metabolism. With widespread use of low P diets containing exogenous phytase, the optimal dietary Ca level was verified. The 40‐day study evaluated the effects of Ca level (4, 7 and 10 g/kg diet) and Ca source (Ca from CaCO₃ and from Lithothamnium calcareum) on mineral utilisation in 72 piglets (7.9 ± 1.0 kg BW) fed an exogenous phytase containing diet with 2.9 g digestible P/kg. Measured parameters were growth performance, stomach mineral solubility, bone breaking strength and urinary, serum and bone mineral concentration. The apparent total tract digestibility of minerals was also assessed in the two diets with 7 g Ca/kg, using 12 additional pigs. Regardless of Ca source, increasing dietary Ca impaired feed conversion ratio, increased urinary pH, increased serum and urinary Ca, decreased serum and urinary P, decreased serum Mg and increased urinary Mg, increased serum AP activity, decreased bone Mg increased bone Zn. Bone breaking strength was improved with 7 compared to 4 g Ca/kg. Compared to CaCO₃, Ca from Lithothamnium calcareum increased serum Mg and with, 10 g Ca/kg, it limited body weight gain. The dose response of Ca in a diet with 2.9 g digestible P/kg and including exogenous phytase indicated that: (i) a low dietary Ca was beneficial for piglet growth, but was limiting the metabolic use of P; (ii) a high dietary Ca level impaired P utilisation; (iii) the optimal P utilisation and bone breaking strength was obtained with a dietary Ca‐to‐digestible P ratio of 2.1 to 2.4:1; (iv). Increasing dietary Ca reduced Mg utilisation, but not Zn status, when fed at adequate level. Finally, Ca from Lithothamnium calcareum had similar effects on Ca and P metabolism as CaCO₃, but impaired growth when fed at the highest inclusion level.     

Concentrations of macro- and micro-elements in the milk of pasture-fed thoroughbred mares

OBJECTIVE: To determine the changes in Ca, P, Mg, Na, K, S, Cu, Fe and Zn concentrations of milk during the lactation in pasture-fed Thoroughbred mares and then calculate the dietary mineral requirements of the sucking foal and the lactating mare. PROCEDURE: Milk was sampled on days 1, 3, 7, 14, 21, 28 and at various times between 55 to 65, 85 to 95 and 135 to 150 days after parturition from 21 pasture-fed mares. The concentrations of macro- and micro-elements in the milk were determined by inductively coupled plasma emission spectrometry. RESULTS: Concentrations (mg/L) of these elements were highest in colostrum (Mg 302, Na 561, K 955, S 1035, Cu 0.76, Fe 0.79 and Zn 5.5) except for Ca (1245) and P (895), which where highest on day 7. The mean milk mineral element concentrations (mg/L) over days 55 to 150 were Ca 843, P 543, Mg 47, Na 120, K 590, S 219, Cu 0.19, Fe 0.34 and Zn 2.1. The mean plasma element concentrations (mg/L) over the same period were Ca 120, P 77.1, Mg 17.0, Na 3110, K 168, S 983, Cu 1.1, Fe 1.5 and Zn 0.49. Concentration gradients between plasma and milk were observed and, in the case of Ca, P, Mg, K and Zn, their concentrations in milk were greater than those in plasma, while a reverse situation was observed for Na, S, Cu and Fe. CONCLUSION: With the exception of Ca and P, the highest concentrations of mineral elements were observed in the colostrum. The nursing foal should have access to good pasture or creep feed, because the intakes of Ca, P and Cu from milk may be less than optimum to meet the daily mineral element requirements.     

Evaluation of the mineral status of cattle on communal grazing in the North West Province of South Africa

Twenty five cattle were randomly selected from a herd of animals grazing communally around Mogosane village in the North West Province to evaluate their mineral status based on blood and faecal analysis. Mean faecal phosphorus (P) concentration was curvilinear, increasing from July (0.99 mg/g) to December (3.63 mg/g) and decreasing to 1.29 mg/g in June. Mean P concentration in grass was also curvilinear, increasing from July (0.87 mg/g) to January (1.8 mg/g) and decreasing to 0.9 mg/g in June. There was a high correlation (r2 = 0.89) between faecal and grass P concentrations. Faecal:grass P ratios suggest that the animals were conserving P by reducing faecal P excretion during times of low dietary P. Animals maintained consistent but very low serum inorganic P (SiP) throughout the year (range 1.33-1.95 mg%) and SiP was not correlated with either faecal or grass P. Mean faecal and grass calcium (Ca) concentrations followed a similar pattern to P. There was also a positive correlation (r2 = 0.95) between grass and faecal Ca concentrations. Faecal:grass Ca ratios indicated a conservation of Ca by reducing faecal Ca when dietary Ca was low. Animals were better able to conserve dietary Ca by reducing losses in the faeces than they were P, based on a higher faecal:grass P ratio (1.56) compared with Ca (1.18). Magnesium (Mg) was lost through the faeces during times of high dietary Mg concentrations but was conserved when grass Mg was low.     

Nutrient and metal analyses of Chinese herbal products marketed for veterinary use

Many Chinese herbs and herbal mixtures are fed to domestic animals for their reputed medicinal properties. These herbs could contribute to the intake of essential nutrients and toxic metals, but their composition is mostly unknown. The purpose of this study was to measure major nutrient (crude protein, crude fat, carbohydrate, fibre) and mineral (Ca, P, Mg, K, Na, Fe, Zn, Cu, Mn, Mo, S, Al, Cd, Ni, Pb) concentrations in samples of fourteen combination formulas labelled for veterinary use and commonly administered to horses and dogs. Three single herbs, Bupleurum chinense, Curcuma zedoaria and Astragalus membranaceus, each obtained from several sources, and Yunnan Baiyao, a proprietary hemostatic mixture, were also analysed. Proximate analyses and some mineral concentrations differed (p < 0.05) among single herbs, and high concentrations of several minerals were detected in some herbal combinations. Those containing the highest concentrations [g/kg dry matter (DM)] of calcium (92.4), iron (2.6) and manganese (0.28) could provide >38%, 142% and 96%, respectively, of recommended allowances in adult dogs, and >13%, 122% and 2%, respectively, of maintenance requirements in horses, at the maximum labelled dose assuming complete availability. Concentrations of cadmium, nickel and lead were below published oral tolerance levels. Aluminium concentrations (median 380, maximum 920 mg/kg DM) were higher than has been previously reported in Chinese herbs. These nutrient analyses suggest that herbal combinations marketed to veterinarians, when fed at the maximal labelled dose, are unlikely to produce clinically relevant changes in the dietary intake of essential nutrients. However, small amounts of non‐essential contaminant minerals are present in some formulas, and further research is necessary to understand the significance of this finding.     

Copper and zinc balance in exercising horses fed 2 forms of mineral supplements

Studies comparing the absorption and retention of various forms of trace minerals in horses have yielded mixed results. The objective of this study was to compare Cu and Zn absorption and retention in exercising horses where the mineral was supplemented in the sulfate or organic chelate form. Nine mature horses were used in a modified switchback design experiment consisting of seven 28-d periods. Horses were fed a diet consisting of 50% concentrate and 50% hay that was balanced to meet the energy, protein, Ca, and P requirements for horses performing moderate-intensity exercise. Horses were subjected to a controlled mineral repletion-depletion diet sequence before feeding the experimental diet to standardize mineral status across horses. The experimental diet was designed to provide 90% of the 1989 NRC for Cu and Zn, with supplemental mineral provided in the inorganic sulfate form (CuSO(4) and ZnSO(4)) or the organic chelate form (Cu-Lys and Zn-Met). Feed, fecal, urine, and water samples collected during a total collection during the last 4 d of the experimental diet periods were analyzed to determine apparent absorption and retention of Cu and Zn from the 2 mineral forms. A formulation error caused horses receiving the organic chelate diet to consume about 3 times the amount of Cu and Zn compared with those fed the sulfate-supplemented diet. Copper and Zn intake and fecal excretion were greater (P < 0.05) for horses consuming the organic chelate-supplemented diet. Apparent absorption values for all horses were negative. Apparent Cu absorption and retention as a percentage of intake were greater for horses fed the organic chelate diet (P < 0.05). It is unknown why excretion of Cu and Zn by the horses during the total collection exceeded the mineral intake. Although Cu-Lys seemed to be better absorbed than CuSO(4) and absorption of Zn-Met and ZnSO(4) were not different, these results are tempered by the observation of abnormally high fecal and urinary excretion values for Cu and Zn in the present study.     

Digestible energy intake, dry matter digestibility and mineral status of grazing New Zealand Thoroughbred yearlings

AIM: To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and to determine the effect of Ca, P, Cu, Zn, and Se supplementation on growth rate and degree of physeal swelling in Thoroughbred yearlings grazed on pasture. METHODS: Fourteen yearling horses were randomly allocated to 1 of 2 groups and rotationally grazed on a ryegrass/white clover pasture for 7 months. One group was supplemented daily with a mineral mix. Liveweight changes were recorded at fortnightly intervals and pasture mineral composition determined at monthly intervals. The DM intake (DMI) was determined from daily faecal DM outputs divided by the indigestible DM fraction (1 - digestible DM) determined from a digestibility study. The DEI was determined from the difference between the gross energy intake and the gross energy faecal output. The DM, gross energy content, crude protein (CP), soluble carbohydrate, acid detergent fibre (ADF), neutral detergent fibre (NDF), lipid and mineral composition of pasture offered and faeces were analysed and their digestibility or apparent absorption calculated. RESULTS: The DM digestibility of pasture averaged 0.64 while the daily DMI and DEI of a 350 kg yearling, gaining 0.6 kg liveweight/day, averaged 6.9 kg DM/day and 78 MJ DE/day, respectively. The mineral supplement had no significant effect on the growth of yearlings grazing pasture that had a mineral composition of (g/kg DM) Na 0.17, K 32.8, Ca 3.6, P 3.4, Mg 2.1, S 3.0, and (mg/kg DM) Cu 7.9, Fe 177, Mn 83, Zn 28 and Se 0.016. Plasma Se was elevated (e.g. 40-218 microg/l) by Se supplementation while Cu supplementation had no effect on plasma and liver Cu concentrations. Physeal swelling was observed in all horses, regardless of treatment. CONCLUSION: Good quality ryegrass/white clover pasture that had a DE content of 11.3 MJ/kg DM and adequate mineral composition (as observed in this study, with the possible exception of Se) will provide an adequate intake of nutrients to ensure good growth in yearling horses.     

绵羊宿营法防除天然草地灌木杂草研究Ⅳ新鲜羊粪尿对土壤和植物矿物质元素含量的影响

新鲜绵羊粪尿对土壤和植物矿物质元素含量影响的试验于 1998年在贵州高原草地试验站进行。结果表明 ,绵羊新鲜粪尿加入土壤后 ,土壤 K呈波浪型升高。 K又显著影响土壤 Ca、Fe和Mn的浓度及土壤 p H值。土壤 Na水平呈下降趋势。土壤中 Ca含量与土壤可交换性亚硝态氮和硝态氮显著相关。土壤 Mg的变化不如其他元素变化明显。土壤 Cu受 Ca、Fe和亚硝态氮及硝态氮的影响显著。土壤 Zn比试验前有所下降 ,其含量与土壤铵态氮和亚硝态氮呈显著负相关 ,而与土壤Na、Mg和 Cu呈显著正相关。土壤 Fe在整个试验过程中呈上升趋势 ,UDT处理几乎呈直线上升。土壤 Mn的变化和土壤 K有显著正相关 ,还与铵态氮相关极显著 (R=0 .80 51,P<0 .0 1)。绵羊新鲜粪尿使植物体内 Fe、Zn水平降低 ,但促进植物 Mn的含量升高 ,而对植物 Cu水平影响最小。结果还表明 ,植物体内 K含量受土壤 Cu和 Na的抑制 ,同时还与植物吸收 Mg、Na和 Fe发生拮抗作用 ,促进了植物 Ca的吸收。植物吸收 Na与土壤 Na的浓度显著相关 ,但受到植物吸收 K、Ca和 Mn的抑制。植物 Ca水平与降雨及植物体内 Fe水平呈显著负相关 ,而与土壤可交换性铵态氮和植物体内 K、Mg含量呈显著正相关。植物体内 Mg含量受土壤可交换性铵态氮和硝态氮的显著影响 ,但受土壤 Ca的抑制     

The Status of Selected Minerals in Soil,Forage and Beef Cattle Tissues in a Semi-arid Region of Zimbabwe

Five districts in the Matabeleland region, an arid western area of Zimbabwe, were investigated for the status of Ca, P, Na, Cu and Zn in soil, forage and cattle during the wet and dry seasons over a period of one year. The cattle came from the natural grazing lands and were not supplemented at the time of sampling. Some deficiencies in soil Zn and P were found in the districts of Lupane and Bulilima-mangwe, respectively. Dry season soil Ca, Cu and P concentrations were significantly higher (p < 0.05) than rainy season values owing to leaching in all five districts. Most forage samples had mineral concentrations below the critical levels known to be adequate for animal requirements. Forage levels of Ca, Na, Cu and Zn significantly increased (p < 0.05) with advancing maturity, while P significantly decreased (p < 0.05) in almost all the districts. Marked deficiencies of minerals were found in cattle tissues and these levels followed the seasonal trend seen in the forage. These results indicate that cattle in Matebeleland are deficient in P, Ca, Cu and Zn and that grazing areas in the region cannot provide adequate levels of the five minerals studied.     

西藏那曲地区高寒草地牧草矿物元素动态变化及盈缺分析

测定了那曲地区尼玛县高寒草地不同月份围栏内和围栏外牧草矿物元素（Ca、P、Na、K、Mg、Cu和Zn）含量，并根据元素的吸收率及藏山羊矿物元素需要量，对放牧藏山羊采食牧草中矿物元素的盈缺进行了分析。结果表明：同月份围栏内与围栏外的矿物元素含量差异不显著（P〉0．05），但不同季节的变异很大。夏秋季牧草Ca、P、Na、K、Mg、Cu、Zn的含量（Ca1．25％DM，P0．1419％DM，Na0．06％DM，K1．51％DM，Mg0．28％DM，Cu8．70mg／kg，Zn27．35mg／kg）高于冬春季（Ca0．72％DM，P0．0005％DM，Na0．02％DM，K0．43％DM，Mg0．10％DM，Cu3．02mg／kg，Zn8．49mg／kg）。除Mg和青草期的K能满足藏山羊的需要外，其余元素不能满足藏山羊生长、繁殖和泌乳对矿物元素的需要量。     

Mineral and amino acid composition of beef cattle hooves

Twenty-three Hereford X Shorthorn cattle were used to evaluate the effects of seasonal and dietary changes on the mineral composition (Ca, Mg, Cu, Zn, and S) of hooves. A seasonal pattern was found in the Ca, Mg, and Zn composition of hooves in the 12 cattle evaluated in 1982 and in the 11 cattle evaluated in 1983, with the concentrations of 3 minerals decreasing in winter when dietary change did not occur. Copper concentrations significantly decreased during the 1st year (1982) and had a tendency to decrease during the 2nd year. During the 1983 pasturing season, when effects of seasonal vs dietary change could not be distinguishable, hoof concentrations of Ca and Mg decreased, whereas the inverse trend was observed for Cu and Zn. Seasonal patterns for hoof concentrations of S were not found. Results of mineral analysis of hooves indicated strong correlations between calcium and the other minerals (except S), and between Zn and Cu. Amino acid analyses of hooves of the 11 cattle in 1983 indicated differences in their composition related to dietary changes (winter feeding vs pasture) or to management.     

Effect of captivity and mineral supplementation on body composition and mineral status of mustached bats (Pteronotus parnellii rubiginosus)

We investigated the whole-body crude nutrient (fat, protein, ash) and mineral (Ca, P, Mg, Na, K) composition of mustached bats of three different groups: animals from the wild (n = 6), and animals from captivity on an unsupplemented feeding regime of mealworms (n = 7), and on a feeding regime in which the mealworms were kept on a mineral substrate prior to feeding (n = 6). It was shown that mealworms from the mineral substrate had higher Ca contents than mealworms from the conventional substrates. In an earlier study, differences in bone mineral density had been found between the groups. These differences, however, were not reflected in differences in whole-body composition. Captive animals showed a larger variation in body weight and fat content, indicating potential shortcomings of the dietary and husbandry regime.     

Effects of exogenous somatotropin on the concentration of minerals in the tissues of growing ram lambs

Ten Suffolk ram lambs (mean BW 14.4 +/- 1.0 kg, 9 wk of age) were used to evaluate the effects of somatotropin (ST) on the concentration of minerals in tissues. Lambs were treated with daily injections of sterile saline (SAL; n = 5) or with bovine pituitary-extracted ST (.1 mg.kg BW-1.d-1; n = 5) for 13 wk. At slaughter at 22 wk of age, the liver, heart, kidneys, brain, spleen, lungs and testes were removed. Tissues were lyophilized, ground and analyzed for minerals. Daily treatment with ST had no influence on Ca, Na, K or the ratio of Na to K in tissues. Although P was lower (P less than .10) in the liver of ST lambs, the concentration of P remained within a normal range for sheep. The concentrations of both Mg (P less than .10) and Fe (P less than .05) were lower in the spleen of ST lambs. Splenic hypertrophy appeared to occur (P = .13) in ST lambs; the total splenic pool of Mg and of Fe did not differ (P greater than .10) between SAL and ST lambs. The concentration of several other minerals were lower in tissues of ST lambs: Cu in kidneys (P less than .10) and liver (P = .12); Zn (P less than .05) in liver, kidneys and lungs; and Mn in liver (P less than .05). By causing a reduction in the concentration of minerals in tissues, ST may increase the possibility of a metabolic insufficiency of a mineral. Exogenous treatment of animals with ST may modify the metabolic requirements for minerals and thereby increase dietary requirements.